Carbonation in Lambic: Difference between revisions

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==Overview==

Carbonation is formed by the dissolution of ~~CO2~~ in a liquid. This carbonation may be the result of microbial action, or forced into the liquid from an external source. In lambic, only the former is traditionally responsible for carbonation in bottles, but the latter may be used, at least to some extent, to force the beer out of the keg or to augment the carbonation in the bottle.

Carbonation is formed by the dissolution of CO2 in a liquid. This carbonation may be the result of microbial action, or forced into the liquid from an external source. In lambic, only the former is traditionally responsible for carbonation in bottles, but the latter may be used, at least to some extent, to force the beer out of the keg or to augment the carbonation in the bottle.

The fermentation of sugars into ethanol releases ~~CO2~~ and is the primary source of the gas in lambic. Thus, the production of alcohol correlates well with the production of ~~CO2~~ and sacharomyces is the primary producer of carbonation in lambic with brettanomyces in a distant second [REF].

The fermentation of sugars into ethanol releases CO2 and is the primary source of the gas in lambic. Thus, the production of alcohol correlates well with the production of CO2 and sacharomyces is the primary producer of carbonation in lambic with brettanomyces in a distant second [REF].

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Carbonation in lambic, as in most beer, is primarily due to the fermentation of simple sugars by saccharomyces [REF]. For glucose, this reaction's overall form is:

C6H12O6 --> ~~CO2~~ + H2O + stuff + energy

C6H12O6 --> CO2 + H2O + stuff + energy

Saccharomyces dominates the yeast flora in lambic between XXX and YYY months[REF], during which time most carbonation is formed. Unblended lambic bottled after this time is generally still as the ~~CO2~~ will have escaped prior to bottling. Lambic bottled younger than this, such as the use of jonge lambic as a blending component in Gueuze, will carbonate in the bottle.

Saccharomyces dominates the yeast flora in lambic between XXX and YYY months[REF], during which time most carbonation is formed. Unblended lambic bottled after this time is generally still as the CO2 will have escaped prior to bottling. Lambic bottled younger than this, such as the use of jonge lambic as a blending component in Gueuze, will carbonate in the bottle.

The addition of simple sugars at the time of bottling, either in fresh wort or in priming sugar, has been shown to re-start fermentation by saccharomyces and lead to carbonation [REF]. This indicates that the end of sacc dominance in the lambic is due to a lack of sugars the yeast can metabolize and not due to inhibition from ethanol or other compounds.

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==The Concentration of Carbon Dioxide in Lambic and Other Beers==

Measurements of carbonation can be reported in volumes of ~~CO2~~ dissolved in the beer. By dividing both by the volume of the liquid, we arrive at a dimensionless number called "volumes of ~~CO2~~". So if one liter of carbon dioxide at cellar temperature and pressure ("CTP", 55 F, 1 atm) is dissolved in one liter of lambic, we may say that this beer contains "one volume of ~~CO2~~". As the molar volume of ~~CO2~~ at CTP is 0.043 mol/l [NIST WEBBOOK], we can convert from "volumes of ~~CO2~~" to molarity by multiplying the former by 0.043. Note that this measures the volume of ~~CO2~~ applied, and thus the total carbon in the system irrespective of whether it's in the form of aqueous ~~CO2~~, carbonic acid, or any of its deprotonations.

Measurements of carbonation can be reported in volumes of CO2 dissolved in the beer. By dividing both by the volume of the liquid, we arrive at a dimensionless number called "volumes of CO2". So if one liter of carbon dioxide at cellar temperature and pressure ("CTP", 55 F, 1 atm) is dissolved in one liter of lambic, we may say that this beer contains "one volume of CO2". As the molar volume of CO2 at CTP is 0.043 mol/l [NIST WEBBOOK], we can convert from "volumes of CO2" to molarity by multiplying the former by 0.043. Note that this measures the volume of CO2 applied, and thus the total carbon in the system irrespective of whether it's in the form of aqueous CO2, carbonic acid, or any of its deprotonations.

Labic ranges from still lambic with 0 volumes of ~~CO2~~ (0 molar) to upwards of 5 volumes of ~~CO2~~ (0.2 molar) in the case of some highly-~~carboned~~ guezes [REF].

Labic ranges from still lambic with 0 volumes of CO2 (0 molar) to upwards of 5 volumes of CO2 (0.2 molar) in the case of some highly-carbonated guezes [REF].

Measurements of carbonation in lambic are shown below along with other beers and carbonated beverages for comparison:

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When dissolved in water, carbon dioxide forms carbonic acid with its solvent via:

~~CO2~~ + H2O -> H2CO3

CO2 + H2O -> H2CO3

at a ratio of about one H2CO3 molecule per 590 dissolved ~~CO2~~ molecules [REF, CRC handbook?]. Carbonic acid has pKas of ~3.49 and ~10.32 [PINES 2016], which are defined as:

at a ratio of about one H2CO3 molecule per 590 dissolved CO2 molecules [REF, CRC handbook?]. Carbonic acid has pKas of ~3.49 and ~10.32 [PINES 2016], which are defined as:

Ka_1 = [H+][HCO3-]/[H2CO3]

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Thus, we can see that the first deprotonation completely dominates the acidity of carbonic acid at low pH, being seven orders of magnitude larger than the second, and we are justified in ignoring the second deprotonation's contribution henceforth. Combining the coefficient of hydration from above with the first deprotonation gives an overall equilibrium constant defined as:

K_total = 4.47*10^-7 = [H+][HCO3-]/([H2CO3] + [~~CO2~~ (aq)]) [REF].

K_total = 4.47*10^-7 = [H+][HCO3-]/([H2CO3] + [CO2 (aq)]) [REF].

Note that the denominator is the total concentration of ~~CO2~~ and products to an approximation better than one part in two million. Combining this with the total carbon from above and re-arranging, we can write

Note that the denominator is the total concentration of CO2 and products to an approximation better than one part in two million. Combining this with the total carbon from above and re-arranging, we can write

[~~CO2~~ (aq)] = (4.3*10^-2(pH+1))~~V_CO2~~/((1+Ka_0)*10^-2pH + Ka_0 * Ka_1 * 10^-pH + Ka_0 * Ka_1 * Ka_2)

[CO2 (aq)] = (4.3*10^-2(pH+1))V_CO2/((1+Ka_0)*10^-2pH + Ka_0 * Ka_1 * 10^-pH + Ka_0 * Ka_1 * Ka_2)

[H2CO3] = Ka_0 * [~~CO2~~ (aq)]

[H2CO3] = Ka_0 * [CO2 (aq)]

[HCO3 -] = Ka_1 * [H2CO3] * 10^-pH

[CO3 2-] = Ka_2 * [HCO3 -] * 10^-pH

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Where

Ka_0 = [H2CO3]/[~~CO2~~ (aq)],

Ka_0 = [H2CO3]/[CO2 (aq)],

which uses numbers a brewer is likely to know, pH and volumes of ~~CO2~~ as independent variables.

which uses numbers a brewer is likely to know, pH and volumes of CO2 as independent variables.

As the pH (pH = -log[H+]) of lambic is lower than most other beers (~3.4 for lambic vs. ~4.5 for non-acidic beers [Embrace the Funk, etc.]), and the volume of ~~CO2~~ can be comparatively larger (~5 volumes for some geuze vs. ~2.5 volumes for your average American Pale Lager), the chemical environment due to carbonation is markedly different:

As the pH (pH = -log[H+]) of lambic is lower than most other beers (~3.4 for lambic vs. ~4.5 for non-acidic beers [Embrace the Funk, etc.]), and the volume of CO2 can be comparatively larger (~5 volumes for some geuze vs. ~2.5 volumes for your average American Pale Lager), the chemical environment due to carbonation is markedly different:

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The prickly mouthfeel of carbonation is partially attributed to the human body's pain sensing system, specifically those pain sensors that express the TRPA-1 protein, which responds to the local pH drop due to the presence of carbonation (as well as mustard and cinnamon) on the tongue with a sharp, tingling sensation. The mechanical sensation of a large amount of gas nucleating and coming out of solution quickly as it warms is responsible for the rest of the sensation (note that the solubility of gasses in liquids generally decreases with temperature) [WANG, CHANG, and LIMAN, 2010].

The human body maintains a blood pH in a very narrow range between 7.35 and 7.45 pH, and is very good at buffering itself. Dissolved ~~CO2~~ in a beer has no significant effect on the body's pH [The Effects of Carbonated Beverages on Arterial Oxygen Saturation, Serum Hemoglobin Concentration and Maximal Oxygen Consumption].

The human body maintains a blood pH in a very narrow range between 7.35 and 7.45 pH, and is very good at buffering itself. Dissolved CO2 in a beer has no significant effect on the body's pH [The Effects of Carbonated Beverages on Arterial Oxygen Saturation, Serum Hemoglobin Concentration and Maximal Oxygen Consumption].

==Other Gasses in Lambic==

In contrast to ~~CO2~~, most other common gasses like nitrogen are much less soluble in water, leading to a much different drinking experience for nitro beers. Also, the helium beer thing is a prank. Helium isn't very soluble in water and most of it would be drunk, not inhaled.

In contrast to CO2, most other common gasses like nitrogen are much less soluble in water, leading to a much different drinking experience for nitro beers. Also, the helium beer thing is a prank. Helium isn't very soluble in water and most of it would be drunk, not inhaled.

Oxygen has a reasonable solubility in water (https://water.usgs.gov/owq/FieldManual/Chapter6/table6.2_6.pdf), and its presence or lack thereof is very important to the ecosystem in the bottle and the final lambic, as well as the slow oxidation of the product as it ages. These effects are outside the scope of this article.

@@ Line 3: / Line 3: @@
 ==Overview==
-Carbonation is formed by the dissolution of CO2 in a liquid. This carbonation may be the result of microbial action, or forced into the liquid from an external source. In lambic, only the former is traditionally responsible for carbonation in bottles, but the latter may be used, at least to some extent, to force the beer out of the keg or to augment the carbonation in the bottle.
+Carbonation is formed by the dissolution of CO<sub>2</sub> in a liquid. This carbonation may be the result of microbial action, or forced into the liquid from an external source. In lambic, only the former is traditionally responsible for carbonation in bottles, but the latter may be used, at least to some extent, to force the beer out of the keg or to augment the carbonation in the bottle.
-The fermentation of sugars into ethanol releases CO2 and is the primary source of the gas in lambic. Thus, the production of alcohol correlates well with the production of CO2 and sacharomyces is the primary producer of carbonation in lambic with brettanomyces in a distant second [REF].
+The fermentation of sugars into ethanol releases CO<sub>2</sub> and is the primary source of the gas in lambic. Thus, the production of alcohol correlates well with the production of CO<sub>2</sub> and sacharomyces is the primary producer of carbonation in lambic with brettanomyces in a distant second [REF].
@@ Line 12: / Line 12: @@
 Carbonation in lambic, as in most beer, is primarily due to the fermentation of simple sugars by saccharomyces [REF]. For glucose, this reaction's overall form is:
-C6H12O6 --> CO2 + H2O + stuff + energy
+C6H12O6 --> CO<sub>2</sub> + H2O + stuff + energy
-Saccharomyces dominates the yeast flora in lambic between XXX and YYY months[REF], during which time most carbonation is formed. Unblended lambic bottled after this time is generally still as the CO2 will have escaped prior to bottling. Lambic bottled younger than this, such as the use of jonge lambic as a blending component in Gueuze, will carbonate in the bottle.
+Saccharomyces dominates the yeast flora in lambic between XXX and YYY months[REF], during which time most carbonation is formed. Unblended lambic bottled after this time is generally still as the CO<sub>2</sub> will have escaped prior to bottling. Lambic bottled younger than this, such as the use of jonge lambic as a blending component in Gueuze, will carbonate in the bottle.
 The addition of simple sugars at the time of bottling, either in fresh wort or in priming sugar, has been shown to re-start fermentation by saccharomyces and lead to carbonation [REF]. This indicates that the end of sacc dominance in the lambic is due to a lack of sugars the yeast can metabolize and not due to inhibition from ethanol or other compounds.
@@ Line 23: / Line 23: @@
 ==The Concentration of Carbon Dioxide in Lambic and Other Beers==
-Measurements of carbonation can be reported in volumes of CO2 dissolved in the beer. By dividing both by the volume of the liquid, we arrive at a dimensionless number called "volumes of CO2". So if one liter of carbon dioxide at cellar temperature and pressure ("CTP", 55 F, 1 atm) is dissolved in one liter of lambic, we may say that this beer contains "one volume of CO2". As the molar volume of CO2 at CTP is 0.043 mol/l [NIST WEBBOOK], we can convert from "volumes of CO2" to molarity by multiplying the former by 0.043. Note that this measures the volume of CO2 applied, and thus the total carbon in the system irrespective of whether it's in the form of aqueous CO2, carbonic acid, or any of its deprotonations.
+Measurements of carbonation can be reported in volumes of CO<sub>2</sub> dissolved in the beer. By dividing both by the volume of the liquid, we arrive at a dimensionless number called "volumes of CO<sub>2</sub>". So if one liter of carbon dioxide at cellar temperature and pressure ("CTP", 55 F, 1 atm) is dissolved in one liter of lambic, we may say that this beer contains "one volume of CO<sub>2</sub>". As the molar volume of CO<sub>2</sub> at CTP is 0.043 mol/l [NIST WEBBOOK], we can convert from "volumes of CO<sub>2</sub>" to molarity by multiplying the former by 0.043. Note that this measures the volume of CO<sub>2</sub> applied, and thus the total carbon in the system irrespective of whether it's in the form of aqueous CO<sub>2</sub>, carbonic acid, or any of its deprotonations.
-Labic ranges from still lambic with 0 volumes of CO2 (0 molar) to upwards of 5 volumes of CO2 (0.2 molar) in the case of some highly-carboned guezes [REF].
+Labic ranges from still lambic with 0 volumes of CO<sub>2</sub> (0 molar) to upwards of 5 volumes of CO<sub>2</sub> (0.2 molar) in the case of some highly-carbonated guezes [REF].
 Measurements of carbonation in lambic are shown below along with other beers and carbonated beverages for comparison:
@@ Line 36: / Line 36: @@
 When dissolved in water, carbon dioxide forms carbonic acid with its solvent via:
-CO2 + H2O -> H2CO3
+CO<sub>2</sub> + H2O -> H2CO3
-at a ratio of about one H2CO3 molecule per 590 dissolved CO2 molecules [REF, CRC handbook?]. Carbonic acid has pKas of ~3.49 and ~10.32 [PINES 2016], which are defined as:
+at a ratio of about one H2CO3 molecule per 590 dissolved CO<sub>2</sub> molecules [REF, CRC handbook?]. Carbonic acid has pKas of ~3.49 and ~10.32 [PINES 2016], which are defined as:
 Ka_1 = [H+][HCO3-]/[H2CO3]
@@ Line 49: / Line 49: @@
 Thus, we can see that the first deprotonation completely dominates the acidity of carbonic acid at low pH, being seven orders of magnitude larger than the second, and we are justified in ignoring the second deprotonation's contribution henceforth. Combining the coefficient of hydration from above with the first deprotonation gives an overall equilibrium constant defined as:
-K_total = 4.47*10^-7 = [H+][HCO3-]/([H2CO3] + [CO2 (aq)]) [REF].
+K_total = 4.47*10^-7 = [H+][HCO3-]/([H2CO3] + [CO<sub>2</sub> (aq)]) [REF].
-Note that the denominator is the total concentration of CO2 and products to an approximation better than one part in two million. Combining this with the total carbon from above and re-arranging, we can write
+Note that the denominator is the total concentration of CO<sub>2</sub> and products to an approximation better than one part in two million. Combining this with the total carbon from above and re-arranging, we can write
-[CO2 (aq)] = (4.3*10^-2(pH+1))V_CO2/((1+Ka_0)*10^-2pH + Ka_0 * Ka_1 * 10^-pH + Ka_0 * Ka_1 * Ka_2)
+[CO<sub>2</sub> (aq)] = (4.3*10^-2(pH+1))V_CO<sub>2</sub>/((1+Ka_0)*10^-2pH + Ka_0 * Ka_1 * 10^-pH + Ka_0 * Ka_1 * Ka_2)
-[H2CO3] = Ka_0 * [CO2 (aq)]
+[H2CO3] = Ka_0 * [CO<sub>2</sub> (aq)]
 [HCO3 -] = Ka_1 * [H2CO3] * 10^-pH
 [CO3 2-] = Ka_2 * [HCO3 -] * 10^-pH
@@ Line 60: / Line 60: @@
 Where
-Ka_0 = [H2CO3]/[CO2 (aq)],
+Ka_0 = [H2CO3]/[CO<sub>2</sub> (aq)],
-which uses numbers a brewer is likely to know, pH and volumes of CO2 as independent variables.
+which uses numbers a brewer is likely to know, pH and volumes of CO<sub>2</sub> as independent variables.
-As the pH (pH = -log[H+]) of lambic is lower than most other beers (~3.4 for lambic vs. ~4.5 for non-acidic beers [Embrace the Funk, etc.]), and the volume of CO2 can be comparatively larger (~5 volumes for some geuze vs. ~2.5 volumes for your average American Pale Lager), the chemical environment due to carbonation is markedly different:
+As the pH (pH = -log[H+]) of lambic is lower than most other beers (~3.4 for lambic vs. ~4.5 for non-acidic beers [Embrace the Funk, etc.]), and the volume of CO<sub>2</sub> can be comparatively larger (~5 volumes for some geuze vs. ~2.5 volumes for your average American Pale Lager), the chemical environment due to carbonation is markedly different:
@@ Line 74: / Line 74: @@
 The prickly mouthfeel of carbonation is partially attributed to the human body's pain sensing system, specifically those pain sensors that express the TRPA-1 protein, which responds to the local pH drop due to the presence of carbonation (as well as mustard and cinnamon) on the tongue with a sharp, tingling sensation. The mechanical sensation of a large amount of gas nucleating and coming out of solution quickly as it warms is responsible for the rest of the sensation (note that the solubility of gasses in liquids generally decreases with temperature) [WANG, CHANG, and LIMAN, 2010].
-The human body maintains a blood pH in a very narrow range between 7.35 and 7.45 pH, and is very good at buffering itself. Dissolved CO2 in a beer has no significant effect on the body's pH [The Effects of Carbonated Beverages on Arterial Oxygen Saturation, Serum Hemoglobin Concentration and Maximal Oxygen Consumption].
+The human body maintains a blood pH in a very narrow range between 7.35 and 7.45 pH, and is very good at buffering itself. Dissolved CO<sub>2</sub> in a beer has no significant effect on the body's pH [The Effects of Carbonated Beverages on Arterial Oxygen Saturation, Serum Hemoglobin Concentration and Maximal Oxygen Consumption].
 ==Other Gasses in Lambic==
-In contrast to CO2, most other common gasses like nitrogen are much less soluble in water, leading to a much different drinking experience for nitro beers. Also, the helium beer thing is a prank. Helium isn't very soluble in water and most of it would be drunk, not inhaled.
+In contrast to CO<sub>2</sub>, most other common gasses like nitrogen are much less soluble in water, leading to a much different drinking experience for nitro beers. Also, the helium beer thing is a prank. Helium isn't very soluble in water and most of it would be drunk, not inhaled.
 Oxygen has a reasonable solubility in water (https://water.usgs.gov/owq/FieldManual/Chapter6/table6.2_6.pdf), and its presence or lack thereof is very important to the ecosystem in the bottle and the final lambic, as well as the slow oxidation of the product as it ages. These effects are outside the scope of this article.